Systems and methods for seismic data acquisition employing asynchronous, decoupled data sampling and transmission

• US 7,660,203 B2
• Filed: 03/08/2007
• Issued: 02/09/2010
• Est. Priority Date: 03/08/2007
• Status: Expired due to Fees

• Current Assignee: WesternGeco LLC
• Original Assignee: WesternGeco LLC
• Inventors: Barakat, Simon, Iranpour, Kambiz, Golparian, Daniel H.
• Primary Examiner(s): Lobo; Ian J
• Application Number:
  US11/683,883
• Publication Number:
  US 20080219094A1
• Time in Patent Office: 1,069 Days
• Field of Search: 367/59, 367/63, 367/76
• US Class Current: 367/76
• CPC Class Codes: G01V 1/22 Transmitting seismic signals to recording or processing apparatus
• CPC Class Codes: G01V 1/247 Digital recording of seismic data, e.g. in acquisition units or nodes

Abstract

Systems and methods for asynchronously acquiring seismic data are described, one system comprising one or more seismic sources, a plurality of sensor modules each comprising a seismic sensor, an A/D converter for generating digitized seismic data, a digital signal processor (DSP), and a sensor module clock; a seismic data recording station; and a seismic data transmission sub-system comprising a high precision clock, the sub-system allowing transmission of at least some of the digitized seismic data to the recording station, wherein each sensor module is configured to periodically receive from the sub-system an amount of the drift of its clock relative to the high precision clock.

Claims

1. A method comprising:

a) initiating one or more seismic sources;

b) asynchronously acquiring reflected analog seismic data using a sensor system, the sensor system comprising a plurality of sensor modules, each comprising a seismic sensor, an A/D converter (ADC) for generating digitized seismic data from the analog data, a digital signal processor (DSP), and a sensor module clock;

c) transmitting at least some of the digitized seismic data to a data recording station via a data transmission sub-system comprising a high precision clock having a high precision clock frequency; and

d) correcting clock frequency drift of each sensor module clock relative to the data transmission sub-system high precision clock frequency by configuring each sensor module to periodically receive from the sub-system an amount of drift of the sensor module clock relative to the high precision clock.

2. The method of claim 1 comprising each DSP upsampling the digitized seismic data at a first fixed sampling rate relative to the high precision clock.

3. The method of claim 2 comprising each DSP upsampling the digitized seismic data using an interpolation technique selected from linear and nonlinear interpolation, based on the amount of drift of each sensor module clock relative to the data transmission sub-system high precision clock, to increase each sensor module'"'"'s effective sampling rate.

4. The method of claim 1, comprising each DSP periodically downsampling the digitized seismic data at a second fixed sampling rate relative to the high precision clock.

5. The method of claim 1, comprising strategically positioning one or more base stations to receive the digitized seismic data from corresponding one or more groups of sensor modules via first wireless links.

6. The method of claim 5, further comprising at least one group of sensor modules relaying at least some of the digitized seismic data wirelessly within the group from sensor module to sensor module via a communication topology selected from a partial mesh topology, a mesh topology, and a star topology.

7. The method of claim 5, further comprising at least one group of sensor modules relaying data packets wirelessly within the group from sensor module to sensor module via multi-hopping.

8. The method of claim 5, wherein the base station is selected from mobile and non-mobile communication devices.

9. The method of claim 5, wherein the first wireless links are selected from wireless personal area network (WPAN) communication protocols.

10. The method of claim 9, wherein the personal area network (WPAN) communication protocols are independently selected from protocols covered by IEEE standard 802.15.

11. The method of claim 1, wherein correcting clock frequency drift of each sensor module clock relative to the data transmission sub-system high precision clock frequency further comprises configuring each sensor module to periodically receive information from a global positioning system sufficient to calculate an amount of drift of the sensor module clock relative to the high precision clock.